JP7013672B2 - Image forming device and program - Google Patents

Description

The present invention relates to an image forming apparatus and a program.

Conventionally, in an image forming apparatus using an electrophotographic method, as a means for removing residual toner such as untransferred toner and transfer residual toner on an image carrier, for example, a cleaning member such as a flat plate-shaped cleaning blade made of an elastic body is used. There is known a blade cleaning type cleaning device that abuts the toner on the surface of the image carrier and thereby removes the residual toner on the image carrier.

In recent years, there has been a demand for smaller particle sizes of toner particles in an electrophotographic image forming apparatus from the viewpoint of improving image quality, and examples of methods for obtaining such toner particles include an emulsion polymerization method and a suspension polymerization method. The polymerization method of is used. However, as the particle size of the toner particles becomes smaller, the adhesive force between the toner particles and the image carrier increases, which makes it difficult to remove the residual toner on the image carrier. In particular, when a so-called polymerized toner produced by a polymerization method is used, the shape of the toner particles becomes close to a sphere, and a cleaning defect called "slinque", which passes through the cleaning blade, is likely to occur, and the image is imaged. There is a problem that it becomes more difficult to remove the residual toner on the carrier. Further, agglomerates of toner may be formed on the image carrier with the toner that has passed through the cleaning blade as a nucleus, and granular white spots (granular noise) may occur in the solid image printing portion.

In order to deal with such quality problems such as "slinking" and "granular noise", at present, a lubricant is supplied on the image carrier and cleaning is performed with the adhesive force between the toner particles and the image carrier reduced. (For example, see Patent Document 1). As a method of supplying the lubricant on the image carrier, a lubricant application method in which the brush is brought into contact with the rod-shaped lubricant and the lubricant is scraped off with the brush, or a toner image containing the lubricant is used to create a toner image. However, there is a toner external addition method that supplies lubricant.
If the amount of lubricant on the image carrier is small, there are problems such as the above-mentioned quality problems such as "slinking" and "granular noise", and problems such as increased wear of the image carrier and shortening of the life of the image carrier. On the other hand, if the amount of lubricant on the image carrier is too large, there is a problem that the wear of the cleaning blade increases, so that the amount of lubricant on the latent image carrier has an appropriate range.
The lubricant on the image carrier is recovered by a cleaning blade or the like, and the recovered amount varies depending on the amount of toner deposited on the cleaning blade or the like. Therefore, even if a certain amount of lubricant is supplied on the image carrier, the image carrier The amount of lubricant on the top varies.
Therefore, in order to maintain the amount of lubricant on the image carrier within an appropriate range, it is necessary to control the supply amount and recovery amount of the lubricant.

Japanese Unexamined Patent Publication No. 9-62163

By the way, when a lubricant having the same polarity as the toner is supplied to the image carrier, the lubricant may move to the intermediate transfer belt due to the transfer electric field. In particular, in a color image forming apparatus, the transfer electric field must be increased in the downstream image forming portion, so that the amount of lubricant decreases in the downstream image forming portion.
On the other hand, when the charge polarity of the lubricant is opposite to that of the toner, the lubricant does not transfer to the intermediate transfer belt, so that there is no concern about the lack of the lubricant.

However, "reverse transfer" may occur in which the upstream color toner transferred to the intermediate transfer belt is retransferred onto the downstream color image carrier, and the amount of toner reaching the cleaning blade is a self-colored transfer residue. In addition to the toner amount, the reverse transfer toner amount of the upstream color is also added. As a result, the amount of toner reaching the cleaning blade increases, so that the recovery of the lubricant by the cleaning blade is promoted, and the amount of the lubricant in the downstream color becomes smaller.
Therefore, in the case of a color machine, even if a lubricant having a polarity opposite to that of the toner is used, the amount of the lubricant on the image carrier of the downstream color is reduced due to the influence of the reverse transfer toner of the upstream color. Since the amount of lubricant on the image carrier has an appropriate range, it is necessary to keep the amount of lubricant on the image carrier of each color within a certain range. It is necessary to increase the supply amount. Even on the image carrier of the most upstream color in which the reverse transfer toner does not exist, if the same amount of lubricant as that of the downstream color is used, the supply will be excessive. As a result, there arises a problem that the life of the cleaning blade of the most upstream color is shortened.

The present invention has been made in view of the above problems, and provides an image forming apparatus and a program capable of optimizing the life balance of an image carrier and a cleaning member in an image forming apparatus having a plurality of image forming portions. The purpose is to do.

In order to solve the above problem, the image forming apparatus according to claim 1 is
An intermediate transfer body that transfers the toner image to paper,
A plurality of image-forming devices arranged along the rotation direction of the intermediate transfer member, and the like.
The image-making device is
An image carrier that supports a toner image to be transferred to paper,
A charging device for charging the image carrier and
A developing device that supplies toner to the image carrier and develops the toner image,
It is provided with a cleaning member which is arranged downstream of the transfer position with the intermediate transfer body and upstream of the charging device in the rotation direction of the image carrier and abuts on the image carrier to clean the surface.
A lubricant having the opposite polarity to the toner supplied by the developing device is supplied to the image carrier.
The amount of lubricant supplied to the image carrier of one image-forming device arranged at the uppermost stream in the rotational direction of the intermediate transfer member is smaller than the amount of lubricant supplied to the image-bearing body of the other image-bearing device. Moreover, the amount of toner transferred from the one image forming apparatus to the intermediate transfer body is an amount corresponding to the amount of reverse transfer toner which is the amount of toner reversely transferred from the intermediate transfer body to the other image forming apparatus. It is characterized by.

The image forming apparatus according to claim 2 is
An intermediate transfer body that transfers the toner image to paper,
A plurality of image-forming devices arranged along the rotation direction of the intermediate transfer member, and the like.
The image-making device is
An image carrier that supports a toner image to be transferred to paper,
A charging device for charging the image carrier and
A developing device that supplies toner to the image carrier and develops the toner image,
It is provided with a cleaning member which is arranged downstream of the transfer position with the intermediate transfer body and upstream of the charging device in the rotation direction of the image carrier and abuts on the image carrier to clean the surface.
The amount of lubricant supplied to the image carrier of one image-forming device arranged at the uppermost stream in the rotational direction of the intermediate transfer body is smaller than the amount of lubricant supplied to the image carrier of the other image-bearing device.
A lubricant supply device arranged downstream from the transfer position with the intermediate transfer member in the rotation direction of the image carrier and supplying the image carrier with a lubricant having the opposite polarity to the toner supplied by the developing device.
A control unit for controlling the amount of lubricant supplied in the lubricant supply device is further provided.
The control unit determines the amount of lubricant supplied in the lubricant supply device of the other image-forming device, the transfer voltage in the image-forming device, and the image area ratio of the toner image imaged in at least one image-forming device. Control based on
It is characterized by that.
The image forming apparatus according to claim 3 is
An intermediate transfer body that transfers the toner image to paper,
A plurality of image-forming devices arranged along the rotation direction of the intermediate transfer member, and the like.
The image-making device is
An image carrier that supports a toner image to be transferred to paper,
A charging device for charging the image carrier and
A developing device that supplies toner to the image carrier and develops the toner image,
It is provided with a cleaning member which is arranged downstream of the transfer position with the intermediate transfer body and upstream of the charging device in the rotation direction of the image carrier and abuts on the image carrier to clean the surface.
The amount of lubricant supplied to the image carrier of one image-forming device arranged at the uppermost stream in the rotational direction of the intermediate transfer body is smaller than the amount of lubricant supplied to the image carrier of the other image-bearing device.
A lubricant supply device arranged downstream from the transfer position with the intermediate transfer member in the rotation direction of the image carrier and supplying the image carrier with a lubricant having the opposite polarity to the toner supplied by the developing device.
A control unit for controlling the amount of lubricant supplied in the lubricant supply device is further provided.
The image-making device is
A measuring unit for measuring the amount of toner transferred from the intermediate transfer body to the image carrier is provided.
The control unit
The lubricant supply amount in the lubricant supply device of the other image-forming device is the toner amount measured by the measuring unit in the image-forming device, and the image area ratio of the toner image imaged by at least one image-forming device. And control based on
It is characterized by that.
The image forming apparatus according to claim 4 is
An intermediate transfer body that transfers the toner image to paper,
A plurality of image-forming devices arranged along the rotation direction of the intermediate transfer member, and the like.
The image-making device is
An image carrier that supports a toner image to be transferred to paper,
A charging device for charging the image carrier and
A developing device that supplies toner to the image carrier and develops the toner image,
It is provided with a cleaning member which is arranged downstream of the transfer position with the intermediate transfer body and upstream of the charging device in the rotation direction of the image carrier and abuts on the image carrier to clean the surface.
The amount of lubricant supplied to the image carrier of one image-forming device arranged at the uppermost stream in the rotational direction of the intermediate transfer body is smaller than the amount of lubricant supplied to the image carrier of the other image-bearing device.
A lubricant supply device arranged downstream from the transfer position with the intermediate transfer member in the rotation direction of the image carrier and supplying the image carrier with a lubricant having the opposite polarity to the toner supplied by the developing device.
A control unit for controlling the amount of lubricant supplied in the lubricant supply device is further provided.
The lubricant feeder comprises a solid lubricant and
The hardness of the solid lubricant in the lubricant supply device of the one image-forming device is higher than the hardness of the solid lubricant in the lubricant supply device of the other image-forming device.
The hardness of the solid lubricant is higher as the lubricant supply device of the image-forming device is arranged upstream in the rotation direction of the intermediate transfer body.
It is characterized by that.
The invention according to claim 5 is the image forming apparatus according to any one of claims 2 to 4 .
The lubricant supply device is
A solid lubricant and a rotating member that abuts on the image carrier and rotates in contact with the solid lubricant are provided.
The control unit
The contact force of the solid lubricant with respect to the rotating member in the lubricant supply device of the one image-forming device is controlled to be weaker than the contact force of the solid lubricant with the rotating member of the lubricant supply device of another image-forming device. It is characterized by doing.

The invention according to claim 6 is the image forming apparatus according to any one of claims 2 to 4 .
The lubricant supply device is
A solid lubricant and a rotating member that abuts on the image carrier and rotates in contact with the solid lubricant are provided.
The control unit
It is characterized in that the rotation speed of the rotating member in the lubricant supply device of the one image-forming device is controlled to be smaller than the rotation speed of the rotating member in the lubricant supply device of the other image-creating device.

The invention according to claim 7 is the image forming apparatus according to any one of claims 2 to 4 .
The lubricant supply device is
A solid lubricant and a pressing member that presses the solid lubricant against the image carrier are provided.
The control unit
It is characterized in that the pressing force of the pressing member in the lubricant supply device of the one image forming device is controlled to be smaller than the pressing force of the pressing member in the lubricant supply device of another image forming device.

The invention according to claim 8 is the image forming apparatus according to any one of claims 2 to 7 .
The control unit is characterized in that the lubricant supply device of the image-forming device arranged upstream in the rotation direction of the intermediate transfer body is controlled so that the lubricant supply amount is smaller.

The image forming apparatus according to claim 9 is
An intermediate transfer body that transfers the toner image to paper,
A plurality of image-forming devices arranged along the rotation direction of the intermediate transfer member, and the like.
The image-making device is
An image carrier that supports a toner image to be transferred to paper,
A charging device for charging the image carrier and
A developing device that supplies toner to the image carrier and develops the toner image,
It is provided with a cleaning member which is arranged downstream of the transfer position with the intermediate transfer body and upstream of the charging device in the rotation direction of the image carrier and abuts on the image carrier to clean the surface.
A lubricant having the opposite polarity to the toner supplied by the developing device is supplied to the image carrier.
The amount of lubricant supplied to the image carrier of one image-forming device arranged at the uppermost stream in the rotational direction of the intermediate transfer body is smaller than the amount of lubricant supplied to the image carrier of the other image-bearing device.
The developing device supplies toner to which a lubricant is added to the image carrier, and the developer supplies the toner.
The amount of the lubricant added to the toner in one image-forming device arranged at the uppermost stream in the rotational direction of the intermediate transfer member is smaller than the amount of the lubricant added to the toner in the other image-forming device. ..

The invention according to claim 10 is the image forming apparatus according to claim 9 .
The image forming apparatus arranged upstream in the rotation direction of the intermediate transfer body is characterized in that the amount of the lubricant added to the toner is small.

The program according to claim 11
The intermediate transfer body for transferring the toner image to the paper and a plurality of image forming devices arranged along the rotation direction of the intermediate transfer body are provided, and the image forming device carries the toner image to be transferred to the paper. Transfer between the image carrier, a charging device that charges the image carrier, a developer that supplies toner to the image carrier and develops a toner image, and an intermediate transfer member in the rotation direction of the image carrier. A cleaning member arranged downstream of the position and upstream of the charging device and in contact with the image carrier to clean the surface, and downstream of the transfer position of the intermediate transfer body in the rotation direction of the image carrier. An image forming apparatus computer provided with a lubricant supply device that is arranged and supplies the lubricant to the image carrier.
The lubricant supply amount in the lubricant supply device of one image-forming device arranged at the uppermost stream in the rotation direction of the intermediate transfer body is controlled to be smaller than the lubricant supply amount in the lubricant supply device of the other image-forming device. To function as a control unit ,
The control unit
The amount of lubricant supplied in the lubricant supply device of the other image-forming device is based on the transfer voltage in the image-forming device and the image area ratio of the toner image imaged in at least one image-forming device.
And then control .
The program according to claim 12
The intermediate transfer body for transferring the toner image to the paper and a plurality of image forming devices arranged along the rotation direction of the intermediate transfer body are provided, and the image forming device carries the toner image to be transferred to the paper. Transfer between the image carrier, a charging device that charges the image carrier, a developer that supplies toner to the image carrier and develops a toner image, and an intermediate transfer member in the rotation direction of the image carrier. A cleaning member arranged downstream of the position and upstream of the charging device and in contact with the image carrier to clean the surface, and downstream of the transfer position of the intermediate transfer body in the rotation direction of the image carrier. An image forming apparatus computer provided with a lubricant supply device that is arranged and supplies the lubricant to the image carrier.
The lubricant supply amount in the lubricant supply device of one image-forming device arranged at the uppermost stream in the rotation direction of the intermediate transfer body is controlled to be smaller than the lubricant supply amount in the lubricant supply device of the other image-forming device. Control unit
To function as
The image-making device is
A measuring unit for measuring the amount of toner transferred from the intermediate transfer body to the image carrier is provided.
The control unit
The lubricant supply amount in the lubricant supply device of the other image-forming device is the toner amount measured by the measuring unit in the image-forming device, and the image area ratio of the toner image imaged by at least one image-forming device. And control based on.
The program according to claim 13 is
An intermediate transfer body for transferring a toner image to paper and a plurality of image forming devices arranged along the rotation direction of the intermediate transfer body are provided, and the image forming device carries a toner image to be transferred to paper. Transfer between the image carrier, a charging device that charges the image carrier, a developing device that supplies toner to the image carrier and develops a toner image, and the intermediate transfer member in the rotation direction of the image carrier. A cleaning member arranged downstream of the position and upstream of the charging device and in contact with the image carrier to clean the surface, and downstream of the transfer position of the intermediate transfer body in the rotation direction of the image carrier. A lubricant supply device, which is arranged and supplies the lubricant to the image carrier, is provided.
The lubricant feeder comprises a solid lubricant and
The hardness of the solid lubricant in the lubricant supply device of the one image-forming device is higher than the hardness of the solid lubricant in the lubricant supply device of the other image-forming device.
The computer of the image forming apparatus having a higher hardness of the solid lubricant as the lubricant supply device of the image forming apparatus arranged upstream in the rotation direction of the intermediate transfer body is used.
The lubricant supply amount in the lubricant supply device of one image-forming device arranged at the uppermost stream in the rotation direction of the intermediate transfer body is controlled to be smaller than the lubricant supply amount in the lubricant supply device of the other image-forming device. Control unit
To function as.
The program according to claim 14
An intermediate transfer body for transferring a toner image to paper and a plurality of image forming devices arranged along the rotation direction of the intermediate transfer body are provided, and the image forming device carries a toner image to be transferred to paper. Transfer between the image carrier, a charging device that charges the image carrier, a developing device that supplies toner to the image carrier and develops a toner image, and the intermediate transfer member in the rotation direction of the image carrier. A cleaning member arranged downstream of the position and upstream of the charging device and in contact with the image carrier to clean the surface, and downstream of the transfer position of the intermediate transfer body in the rotation direction of the image carrier. A lubricant supply device, which is arranged and supplies the lubricant to the image carrier, is provided.
The developing device supplies toner to which a lubricant is added to the image carrier, and the developer supplies the toner.
The computer of the image forming apparatus in which the amount of the lubricant added to the toner in one image forming apparatus arranged at the uppermost stream in the rotation direction of the intermediate transfer member is smaller than the amount of the lubricant added to the toner in the other image forming apparatus. of,
The lubricant supply amount in the lubricant supply device of one image-forming device arranged at the uppermost stream in the rotation direction of the intermediate transfer body is controlled to be smaller than the lubricant supply amount in the lubricant supply device of the other image-forming device. Control unit
To function as.

According to the present invention, it is possible to provide an image forming apparatus and a program capable of making the life balance of an image carrier and a cleaning member suitable in an image forming apparatus having a plurality of image forming portions.

It is a figure which shows the schematic structure of the image forming apparatus which concerns on embodiment to which this invention is applied. It is a block diagram which shows the main functional composition of an image forming apparatus. It is a figure which showed an example of the schematic structure of the image forming part. It is a figure which showed an example of the vertical band chart formed on the photoconductor drum. It is a figure explaining the amount of lubricant on a photoconductor drum. It is a figure explaining the reverse transfer toner adhering on the photoconductor drum. It is a figure explaining the wear amount of the cleaning blade in each image formation part. It is a figure explaining the wear width of a cleaning blade. It is a figure explaining the control method of the contact force of a brush roller. It is a figure which looked at the lubricant coating mechanism from the circumferential direction of a photoconductor drum. It is a figure which showed an example of the schematic structure of the image forming part. It is a figure explaining the relationship between the image area ratio of the upstream color, and the reverse transfer toner. It is a flowchart which shows the operation of the image forming apparatus which concerns on embodiment to which this invention is applied. It is a figure which showed an example of the image forming part which arranged the density sensor. It is a figure which showed an example of the schematic structure of the image forming part. It is a figure which showed an example of the schematic structure of the image forming part.

[First Embodiment]
Hereinafter, the first embodiment according to the image forming apparatus of the present invention will be described with reference to the drawings. In the embodiment of the present invention, a color image forming apparatus will be described as an example, but the present invention is not limited to this, and the present invention is applied to any image forming apparatus having a plurality of image forming portions. It is possible.

<Structure of image forming apparatus>
FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus 1 according to an embodiment of the present invention. FIG. 2 is a block diagram showing a main functional configuration of the image forming apparatus 1.

As shown in FIGS. 1 and 2, the image forming apparatus 1 includes an automatic document conveying unit 2, a scanner unit 3, an image forming unit 4, a paper feeding unit 5, a storage unit 6, an operation display unit 7, and an operation display unit 7. It is configured to include a control unit 10.

The automatic document transport unit 2 is configured to include a mounting tray on which the document D is placed, a mechanism for transporting the document D, a transport roller, and the like, and transports the document D to a predetermined transport path.
The scanner unit 3 is configured to include an optical system such as a light source and a reflecting mirror, irradiates a document D transported along a predetermined transport path or a document D placed on a platen glass with a light source, and receives reflected light. .. Further, the scanner unit 3 converts the received reflected light into an electric signal and outputs it to the control unit 10.

FIG. 3 shows a schematic configuration of the image forming unit 4.
As shown in FIG. 1, the image forming unit 4 has a yellow image forming unit Y, a magenta image forming unit M, a cyan image forming unit C, and a black image forming unit K from the upstream side in the rotation direction of the intermediate transfer belt 451. And the fixing device F are provided.

Each image processing unit (image processing device) is a drum-shaped photoconductor drum 41 (image carrier) that is rotationally driven in the direction a in the figure, and a charging device that uniformly charges the surface of the photoconductor drum 41. 42, an exposure device 43 that exposes the surface of the photoconductor drum 41 charged by the charging device 42 to form an electrostatic latent image, and an electrostatic latent image formed by the exposure device 43 include toner. A developing device 44 for making a visible image using a developer 442, a transfer device 45 for transferring a toner image formed on a photoconductor drum 41 onto paper, and a toner on a photoconductor drum 41 that has passed through a transfer region. In the figure, a toner image formed on the photoconductor drum 41 is provided with a cleaning blade 46 (cleaning member) to be removed and a lubricant application mechanism 47 (lubricant supply device) for applying a lubricant to the surface of the photoconductor drum 41. Primary transfer is performed on the intermediate transfer belt 451 (intermediate transfer body) that moves in the direction of b.
The toner image transferred to the intermediate transfer belt 451 is transferred to a recording material at a secondary transfer position (not shown), then transferred to the fixing device F and fixed on the recording body.

The photoconductor drum 41 is made of an organic photoconductor in which a photosensitive layer made of a resin containing an organic photoconductor is formed on the outer peripheral surface of a drum-shaped metal substrate, and the resin constituting the photosensitive layer is, for example, polycarbonate. Examples thereof include resins, silicone resins, polystyrene resins, acrylic resins, methacrylic resins, epoxy resins, polyurethane resins, vinyl chloride resins, melamine resins and the like.

As the charging device 42, a charging roller or a non-contact charging charger can be used. A power supply (not shown) is connected to the charging device 42, and the photoconductor drum 41 is charged to a constant potential by the voltage output from the power supply. A drive motor (not shown) is attached to the charging device 42, and the charging device 42 rotates in the with direction (direction in which the surface moves in the same direction, direction c in the figure) while in contact with the photoconductor drum 41. , Functions as a rotating member. The peripheral speed of the charging device 42 during image formation is equal to the peripheral speed of the photoconductor drum 41.
After charging by the charging device 42, an electrostatic latent image is formed on the surface of the photoconductor drum 41 by an exposure device 43 such as a laser.

The developing apparatus 44 includes a developing sleeve 441 arranged so as to face the photoconductor drum 41 via a developing region, and a developing agent 442.
For example, a DC development bias having the same polarity as the charging polarity of the charging device 42 or a development bias in which a DC voltage having the same polarity as the charging polarity of the charging device 42 is superimposed on the AC voltage is applied to the developing sleeve 441. Therefore, reverse development is performed in which toner is adhered to the electrostatic latent image formed by the exposure apparatus 43.
The developer 442 contains a toner and a carrier for charging the toner. The toner is not particularly limited, and a commonly used known toner can be used. A colorant and, if necessary, a charge control agent, a mold release agent, etc. are contained in the binder resin, and an external addition is made. A treated agent can be used. The toner particle size is not limited to this, but is preferably about 3 to 15 μm. The carrier is not particularly limited, and a commonly used known carrier can be used, and a binder type carrier, a coat type carrier, or the like can be used. The carrier particle size is not limited to this, but is preferably 15 to 100 μm.

The toner image formed on the photoconductor drum 41 by the developing device 44 is carried to the transfer device 45 provided with the intermediate transfer belt 451 and the transfer roller 452. In the transfer device 45, a voltage having a polarity opposite to that of the toner is applied to the transfer roller 452, and the toner image on the photoconductor drum 41 is first transferred to the intermediate transfer belt 451 and then secondarily transferred to paper.

The toner remaining on the photoconductor drum 41 without being transferred to the intermediate transfer belt 451 by the transfer device 45 is conveyed to the cleaning blade 46 and recovered. As the cleaning blade 46, a flat plate-shaped blade made of an elastic body is used.
The photoconductor drum 41 from which the toner on the surface is recovered by the cleaning blade 46 is charged again by the charging roller 42, the next electrostatic latent image is formed, and the toner image is repeatedly formed.

In the rotation direction of the photoconductor drum 41, a lubricant coating mechanism 47 for applying the lubricant to the photoconductor drum 41 is installed on the downstream side of the contact portion with the intermediate transfer belt 451 and on the upstream side of the cleaning blade 46. .. The lubricant coating mechanism 47 includes at least a brush roller 471 (rotating member) and a solid lubricant 472, and the solid lubricant 472 has the opposite polarity to the toner.
The form of the brush roller 471 is installed so as to be in contact with both the solid lubricant 472 and the photoconductor drum 41, and is rotationally driven by a motor (not shown) to supply lubricant particles carved from the solid lubricant 472 to the photoconductor drum 41. At that time, it also plays a role of spreading and applying the lubricant particles on the photoconductor drum 41 by the contact pressure.

The rotation speed of the brush roller 471 is controlled by changing the rotation speed of a motor (not shown) that rotationally drives the brush roller 471. Increasing the rotation speed increases the coating amount, and decreasing it decreases the coating amount. Further, when the rotation speed is increased, the amount of toner / external additive recovered from the photoconductor drum 41 increases, and when the number of rotations is decreased, the amount of toner / external additive recovered decreases.

As the material of the solid lubricant 472, a material that can be applied to the surface of the photoconductor drum 41 and can reduce the surface energy thereof to reduce the adhesive force between the toner and the photoconductor drum 41 is selected. When a negatively charged toner is used, examples of the positively charged lubricant having the opposite polarity include fatty acid metal salts and fatty acid amides, which may be used alone or in combination of two or more. In particular, fatty acid metal salts are preferable.
As the fatty acid metal salt, as the fatty acid, a linear hydrocarbon is preferable, for example, myristic acid, palmitic acid, stearic acid, oleic acid and the like are preferable, and stearic acid is more preferable. Examples of the metal include lithium, magnesium, calcium, strontium, zinc, cadmium, aluminum, cerium, titanium, iron and the like. Among these, zinc stearate, magnesium stearate, aluminum stearate, iron stearate and the like are preferable, and zinc stearate is most preferable.
When a positively charged toner is used, a negatively charged lubricant is used. In that case, a fluororesin-based lubricant may be used.
The material is melted and molded, or the particles of the material are compression-molded to form a shape that can be machined by a brush roller 471, and used as a solid lubricant 472.

In the present embodiment, the brush roller 471 is further provided with a recovery roller 473 made of a roller in contact with the brush roller 471, and the toner collected by the brush roller 471 from the photoconductor drum 41 is collected before reaching the solid lubricant 472. .. With such a configuration, the toner on the photoconductor drum 41 can be recovered by the rotation of the brush roller 471, and the lubricant can be supplied on the photoconductor drum 41.

The paper feed unit 5 is configured to include a plurality of paper feed trays 51 to 53, and each of the paper feed trays 51 to 53 accommodates a plurality of different types of paper P. The paper feeding unit 5 feeds the paper P accommodated by the predetermined transport path to the image forming unit 4.

The storage unit 6 is composed of an HDD (Hard Disk Drive), a semiconductor memory, and the like, and stores data such as program data and various setting data in a readable and writable manner from the control unit 10. Further, the storage unit 6 stores a predetermined range of the current value of the drive motor M, which will be described later.

The operation display unit 7 is composed of, for example, a liquid crystal display (LCD) with a touch panel, and functions as a display unit 71 and an operation unit 72.
The display unit 71 displays various operation screens, operation status of each function, and the like according to the display control signal input from the control unit 10. Further, it accepts a touch operation by the user and outputs an operation signal to the control unit 10.
The operation unit 72 includes various operation keys such as a numeric keypad and a start key, receives various input operations by the user, and outputs an operation signal to the control unit 10. The user can operate the operation display unit 7 to perform image formation-related settings such as image quality setting, magnification setting, application setting, output setting, and paper setting, paper transport instruction, and stop operation of the device.

The control unit 10 is configured to include a CPU, RAM, ROM, etc., and the CPU expands various programs stored in the ROM into the RAM, and cooperates with the expanded various programs to perform the automatic document transfer unit 2, The operation of each part of the image forming apparatus 1 such as the scanner unit 3, the image forming unit 4, the feeding unit 5, the storage unit 6, and the operation display unit 7 is collectively controlled (see FIG. 2). For example, the control unit 10 inputs an electric signal from the scanner unit 3 to perform various image processing, and outputs the image data Dy, Dm, Dc, and Dk of each color of YMCK generated by the image processing to the image forming unit 4. .. Further, the control unit 10 controls the operation of the image forming unit 4 to form an image on the paper P.

<Amount of lubricant on the photoconductor drum>
Next, the amount of lubricant on the photoconductor drum 41 in the downstream color unit will be described.

FIG. 4 is a schematic view of the surface of the photoconductor drum 41 through which the paper is passed in the X direction. A black vertical band chart (black solid part Ba; position indicated by B) and a yellow vertical band chart (yellow solid part Ya; position indicated by C) are formed in the axial direction (Y direction) of the photoconductor drum 41 to form A3. 3000 sheets of paper were printed.
FIG. 5 shows the results of examining the amount of lubricant on the photoconductor drum 41 of the most downstream color (black image forming portion B) at this time. Further, FIG. 6 shows the state of the toner existing on the photoconductor drum 41 of the black image forming portion B when the apparatus is forcibly stopped while printing the same chart.

As the image forming apparatus 1, a bizhub PRESS C1100 manufactured by Konica Minolta Co., Ltd. was used, and as shown in FIG. 3, an image remodeled into a configuration in which a brush roller 471, a solid lubricant 472, and a recovery roller 473 were provided upstream of the cleaning blade 46. An experiment was conducted using the part.
As the brush roller 471, one made of PET fiber was used. Further, the recovery roller 473 is a GND and the brush roller 471 is a float. The surface of the brush roller 471 rotates in the same direction as the photoconductor drum 41 at a peripheral speed of 640 mm / s. Toner for bizhub PRESS C1100 was used as the developer 442.

The amount of lubricant on the photoconductor drum 41 of the black image forming portion B is determined by A position: yellow and black background portion (no printing), B position: yellow background portion, black solid portion Ba, C position: yellow solid portion Ya, The measurement was performed on the black background.
The amount of lubricant was substituted by the ratio of zinc in zinc stearate determined by the X-ray photoelectron spectroscopy analyzer.

As is clear from FIG. 5, the amount of lubricant at the A position where neither black nor yellow is printed is the largest at about 2 at%. On the other hand, the amount of lubricant at the B position where black is printed is reduced to 1.6 at%. It is considered that this is because the lubricant was recovered by the cleaning blade 46 by the black transfer residual toner. At the C position, the amount of lubricant is reduced even though black is not printed. It is considered that this is because the yellow toner is reverse-transferred to the photoconductor drum 41 of the black image forming portion B, reaches the cleaning blade 46 of the black image forming portion B, and collects the lubricant. The mechanism of generating reverse transfer toner will be described later.

In order to confirm this, we observed the state of toner adhesion on the photoconductor drum 41 of the black image forming part B when the power of the bizhub PRESS C1100 was turned off and forced to stop while printing the same image. .. As a result, as shown in FIG. 6, on the photoconductor drum 41 of the black image forming portion B, the transfer residual toner Bb is located at the B position on the X-direction downstream side of the transfer position T, and the yellow reverse transfer toner Yc is located at the C position. confirmed.
From these results, it can be seen that the amount of lubricant on the photoconductor drum 41 of the downstream color is affected by the reverse transfer toner of the upstream color.

<Control of lubricant supply in each image area>
In FIG. 7, after printing 50,000 charts in which the lubricant supply amount is the same in each image forming portion (the amount that can secure the appropriate lubricant amount on the photoconductor drum 41 in the downstream color) and the image area ratio of each color is 50%. The result of measuring the wear amount of the cleaning blade 46 is shown. As the image forming apparatus 1, the same bizhub PRESS C1100 as at the time of measuring the amount of lubricant on the photoconductor drum 41 described above was used. The amount of wear of the cleaning blade 46 is measured at five points in the axial direction of the photoconductor drum 41 and averaged.
The amount of wear of the cleaning blade 46 was measured using a laser microscope VK-X100 manufactured by KEYENCE Co., Ltd., and the worn area at the contact position between the photoconductor drum 41 and the cleaning blade 46 as shown in FIG. Refers to the width W of.

As is clear from FIG. 7, when the lubricant supply amount is the same, it can be seen that the wear amount of the cleaning blade 46 of the yellow image forming portion Y, which is the most upstream color, is large. It is considered that this is because the reverse transfer toner is not generated in the yellow image forming portion Y of the most upstream color, and the amount of toner reaching the cleaning blade 46 is smaller than that of the downstream color, so that the amount of lubricant recovered is small. If the same amount of lubricant as the downstream color is supplied in this state, it is considered that the amount of lubricant on the photoconductor drum 41 increases and the wear of the cleaning blade 46 increases. When this happens, the life of the yellow unit is shortened.

In order to prevent this, it is necessary for the yellow image forming portion Y of the most upstream color, in which the reverse transfer toner is not generated, to supply less lubricant than the downstream color. Since only the most upstream color is not affected by the reverse transfer toner, at least the amount of lubricant supplied in the image forming portion of the most upstream color may be smaller than the amount of lubricant supplied in other colors.

The amount of lubricant supplied to the photoconductor drum 41 can be changed by controlling the contact force of the solid lubricant 472 with respect to the brush roller 471.
When the contact force is increased, the amount of lubricant scraped from the solid lubricant 472 by the brush roller 471 increases, and as a result, the amount of lubricant supplied to the photoconductor drum 41 also increases. On the contrary, if the contact force of the solid lubricant 472 with respect to the brush roller 471 is reduced, the amount of lubricant supplied to the photoconductor drum 41 can be reduced. Therefore, in order to make the amount of lubricant supplied to the image forming portion of the most upstream color smaller than that of the downstream color, the contact force of the solid lubricant 472 to the brush roller 471 of the image forming portion of the most upstream color is made smaller than the contact force of the downstream color. do it.

9 and 10 show a method of controlling the contact force of the solid lubricant 472.
FIG. 10 is a view seen from the axial direction of the brush roller 471, and FIG. 10 is a view of the state of FIG. 9 seen from the circumferential direction of the brush roller 471.
FIG. 9A shows a state in which the pressure contact force of the solid lubricant 472 with respect to the brush roller 471 is weakened, and FIG. 9B shows a state in which the pressure contact force is strengthened.
The solid lubricant 472 is held by the holding member 474a, and the holding member 474a is guided by the guide 474b and slides along the guide 474b. The solid lubricant 472 is brought into contact with the brush roller 471 by the force of the spring 474c. One of the springs 474c is in contact with the eccentric cam 474d, and the rotation of the eccentric cam 474d changes the set length of the spring 474c, and the pressure contact force of the solid lubricant 472 with the brush roller 471 changes. As shown in FIG. 10, the spring 474c and the eccentric cam 474d are provided on both sides of the brush roller 471 in the axial direction, and the solid lubricant 472 is uniformly in contact with the brush roller 471.

When the eccentric cam 474d is positioned as shown in FIG. 9A, the set length of the spring 474c becomes long, and the pressure contact force of the solid lubricant 472 with the brush roller 471 becomes weak. As a result, the amount of lubricant scraped from the solid lubricant 472 by the brush roller 471 is reduced, and the amount of lubricant supplied onto the photoconductor drum 41 is also reduced. When the eccentric cam 474d is positioned as shown in FIG. 9B, the set length of the spring 474c becomes short, and the pressure contact force of the solid lubricant 472 to the brush roller 471 becomes strong. As a result, the amount of lubricant scraped from the solid lubricant 472 by the brush roller 471 increases, and the amount of lubricant supplied onto the photoconductor drum 41 increases.

Therefore, in the yellow image forming portion Y of the most upstream color, the set length of the spring 474c is set to be long as shown in FIG. 9 (A), and in the downstream color image forming portion, the spring is set as shown in FIG. 9 (B). Set so that the set length of 474c is short. By doing so, the amount of the lubricant supplied onto the photoconductor drum 41 of the most upstream color can be made smaller than the amount of the lubricant supplied onto the photoconductor drum 41 of the downstream color.

Further, in the above description, the case where the contact force of the solid lubricant 472 to the brush roller 471 is changed by changing the set length of the spring 474c has been described. It is also possible to change the contact force of the solid lubricant 472 with the brush roller 471 between the image forming portion of the most upstream color and the image forming portion of the downstream color.
Further, the contact force of the solid lubricant 472 may be changed by a method other than the above.

As described above, in the image forming apparatus 1 according to the first embodiment, the lubricant supply amount is different between the image forming portion of the most upstream color and the image forming portion of the downstream color. That is, by making the supply amount of the lubricant of the most upstream color smaller than the supply amount of the downstream color, the amount of the lubricant on the photoconductor drum 41 can be controlled within a certain range even if it is affected by the reverse transfer toner. It is possible to secure the life of the cleaning blade without causing quality problems such as and granular noise.

Further, the image forming apparatus 1 according to the first embodiment controls the contact force of the solid lubricant 472 with the photoconductor drum 41 by the set length of the spring 474c. Therefore, since the brush roller 471 changes the amount of the lubricant scraped off, the amount of the lubricant supplied can be adjusted during the image formation. Further, even if the lubricant supply amount fluctuates depending on the durability or the environment, the lubricant supply amount can be adjusted within a certain range.

The amount of lubricant supplied to the photoconductor drum 41 can also be changed by controlling the rotation speed of the brush roller 471.
Specifically, when the rotation speed of the brush roller 471 is increased, the width of contact with the photoconductor drum 41 increases per unit time, so that the amount of lubricant supplied to the photoconductor drum 41 increases. On the other hand, when the rotation speed of the brush roller 471 is lowered, the amount of lubricant supplied to the photoconductor drum 41 is reduced.
Therefore, in order to make the supply amount of the lubricant of the most upstream color smaller than that of the downstream color, the number of rotations of the brush roller 471 of the most upstream color may be smaller than that of the downstream color. In order to control the rotation speed of the brush roller 471, a motor that gives a drive to the brush roller 471 may be connected and the rotation speed of the motor may be changed.
In this case, since a mechanical mechanism for changing the set length of the spring 474c as described above is not required, space saving can be achieved.

Further, the solid lubricant 472 is not limited to being brought into contact with the brush roller 471 and supplied to the photoconductor drum 41 via the brush roller 471 as described above, but the solid lubricant 472 is directly brought into contact with the photoconductor drum 41. The lubricant may be supplied to the photoconductor drum 41. The configuration in this case is shown in FIG.
The solid lubricant 472 is in direct contact with the photoconductor drum 41 at the downstream portion of the cleaning blade 46 with respect to the rotation direction of the photoconductor drum 41. A spring 474c (pressing member) is abutted on the solid lubricant 472 by a holding member 474a, a guide 474b, and an eccentric cam 474d (not shown) as in the case of abutting on the brush roller 471, and the photoconductor drum is abutted by the force of the spring 474c. It is pressed against 41. In order to control the amount of lubricant supplied to the photoconductor drum 41, the contact force of the solid lubricant 472 with respect to the photoconductor drum 41 may be controlled. The control mechanism of the contact force of the solid lubricant 472 with respect to the photoconductor drum 41 is the same as that in the case of contacting the brush roller 471, and the configuration shown in FIG. 10 may be used.
In order to change the contact force of the solid lubricant 472 with respect to the photoconductor drum 41, an eccentric cam 474d (not shown) may be rotated to change the set length of the spring 474c. The eccentric cam 474d may be set so that the length of the spring 474c becomes longer.

Further, the amount of lubricant supplied to the photoconductor drum 41 can also be changed by changing the hardness of the solid lubricant 472.
By changing the hardness of the solid lubricant 472, the amount of lubricant scraped by the brush roller 471 can be changed, and the amount of lubricant supplied to the photoconductor drum 41 can be controlled. When the hardness of the solid lubricant 472 is increased, the amount of lubricant scraped by the brush roller 471 decreases, and as a result, the amount of lubricant supplied to the photoconductor drum 41 also decreases. Therefore, in order to reduce the amount of lubricant supplied in the image forming portion of the upstream color to be smaller than that of the downstream color, the hardness of the solid lubricant 472 used for the upstream color may be higher than the hardness of the solid lubricant 472 used for the downstream color.
Further, as described above, only the hardness of the solid lubricant 472 may be changed, or may be combined with the above-mentioned method.
In this case, as compared with the case of controlling the set length of the spring 474c as described above, the lubricant supply amount can be controlled with a simple configuration, and the effect can be obtained at low cost.

In the above embodiment, the lubricant supply amount is set in two stages between the image forming section of the most upstream color and the other image forming section, but the present invention is not limited to this, and each image forming section is not limited to this. The amount of lubricant supplied may be different according to the order from the upstream. This makes it possible to control the lubricant supply amount in consideration of the influence of all the image forming portions located upstream of each image forming portion.

[Second Embodiment]
Next, the image forming apparatus 1 according to the second embodiment will be described.
In the first embodiment, in order to make the lubricant supply amount different between the image forming section of the most upstream color and the image forming section of the downstream color, each image forming section is designed so that the amount of lubricant supplied in the image forming section of the most upstream color is small. However, the image forming apparatus 1 according to the second embodiment controls the lubricant supply amount in the image forming portion of the downstream color according to the toner amount on the photoconductor drum 41. ..
For the sake of simplification of the description, the same components as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

<Relationship between transfer voltage and amount of reverse transfer toner>
The amount of reverse transfer toner reaching the cleaning blade 46 varies depending on the transfer voltage of the downstream color and the amount of toner of the upstream color (image area ratio). Therefore, by detecting these and adjusting the amount of the lubricant for the downstream color, the amount of the lubricant for the downstream color can be controlled more appropriately.

It is generally known that the higher the transfer voltage, the greater the amount of reverse transfer toner.
The reverse transfer toner is considered to be generated as follows. When the transfer voltage applied to the transfer roller 452 becomes high, the current flowing through the photoconductor 41 via the intermediate transfer belt 451 becomes large. If toner is present in that region, the toner charge is attenuated, and toner charged with the opposite polarity to the original is generated. As a result, the reverse transfer toner that moves from the intermediate transfer belt 451 to the photoconductor 41 is generated by the transfer electric field, contrary to the original toner.

Generally, the surface potential of the photoconductor drum 41 before transfer is about −600 V in the background portion and about −50 V in the solid portion. The transfer voltage is a voltage applied to the transfer roller 452 and suitable for transferring the toner existing in the solid portion on the photoconductor drum 41 onto the intermediate transfer belt 451. For example, when a transfer voltage is applied to the transfer roller 452 so that the surface of the intermediate transfer belt 451 becomes 500 V as a voltage suitable for transfer, the potential difference between the intermediate transfer belt 451 and the photoconductor drum 41 in the solid portion is 550 V. However, in the background portion, a potential difference of 1100 V is generated due to the influence of the surface potential of the photoconductor drum 41.

The magenta image forming unit M will be described as an example with reference to FIG. FIG. 12 is a schematic view of the surface of the photoconductor drum 41 of the magenta image forming unit M. When the magenta solid portion Ma is formed as shown in the figure, the outer portion thereof is the magenta background portion Md.
When the self-colored toner (here, magenta) is transferred to the intermediate transfer belt 451, the self-colored toner exists in the magenta solid portion Ma, so that there is a possibility that magenta reverse transfer toner may be generated due to the potential difference in the magenta background portion Md. do not have.
However, there may be an upstream color toner (yellow in this case) present in the magenta background portion Md. As shown in the figure, when the yellow solid portion Ya is present, the potential difference of the intermediate transfer belt 451 in the portion where the magenta background portion Md and the yellow solid portion Ya overlap is large. As a result, the charge of the yellow toner becomes opposite polarity due to the excess current flowing from the intermediate transfer belt 451 to the photoconductor drum 41. As a result, as shown in the figure, the yellow reverse transfer toner Yc that is reverse transferred from the intermediate transfer belt 451 to the photoconductor drum 41 is generated.

The generation rate of the reverse transfer toner can be estimated from the transfer voltage applied to the transfer roller 452. As described above, the background portion has a large potential difference from the surface of the photoconductor drum 41, so that reverse transfer toner is likely to be generated. However, when the transfer voltage is increased, reverse transfer toner is generated even in the solid portion.
On the other hand, even if the transfer voltage is high, if the upstream color toner does not exist on the intermediate transfer belt 451, the reverse transfer toner does not occur in the downstream color.

Therefore, it is necessary to estimate the amount of reverse transfer toner reaching the cleaning blade 46 from the transfer voltage of the own color and the image area ratio of the upstream color.
Since the upstream color toner affects all downstream colors, the amount of lubricant supplied to the downstream color should be determined based on the transfer voltage of the image forming part of that color and at least the image area ratio of the upstream color. preferable.

Furthermore, since the reverse transfer toner is likely to occur in the background portion of the downstream color and the reverse transfer is unlikely to occur in the solid portion of the own color, the lubricant is supplied based on the area ratio of the upstream color and the area ratio of the own color (downstream color). You may decide the amount. Specifically, for example, in the case of the magenta image forming portion M, the magenta area ratio (magenta solid portion Ma in FIG. 12) is subtracted from the yellow area ratio (yellow solid portion Ya in FIG. 12), and the difference (in FIG. 12). The amount of lubricant supplied may be determined based on the yellow reverse transfer toner Yc).

<Control of lubricant supply in the downstream color image area>
The control of the lubricant supply amount in the image forming portion of the downstream color will be described with reference to the flowchart of FIG. The process shown in FIG. 13 is executed in cooperation with the program stored in the control unit 10 and the storage unit 6.

When the job start signal is input (step S1), the control unit 10 determines the image formation conditions and further sets the transfer voltage (step S2).
Here, the transfer voltage applied to the transfer roller 452 may be set to an appropriate value obtained by actually changing the transfer voltage at the time of starting up the image forming apparatus 1 or at the start of the job, or the atmosphere may be set in advance. It may be set to an appropriate value obtained from a table created based on conditions and image information and stored in the storage unit 6.
Since the set appropriate value is also recorded in the storage unit 6, the amount of reverse transfer toner can be calculated based on the transfer voltage. The relationship between the transfer voltage and the amount of reverse transfer toner may be recorded in the storage unit 6 as a table.

Next, the control unit 10 calculates the image area ratio of each color (step S3). The image area ratio can be calculated from the image information of each color of the image to be printed.

From the transfer voltage and the image area ratio obtained in steps S2 and S3, the control unit 10 obtains the amount of reverse transfer toner (step S4).
Here, as described above, in the case of the magenta image forming portion M, the magenta area ratio (magenta solid portion Ma in FIG. 12) is subtracted from the yellow area ratio (yellow solid portion Ya in FIG. 12), and the difference (FIG. 12). The amount of reverse transfer toner is calculated based on the yellow reverse transfer toner Yc).

Next, based on the amount of reverse transfer toner obtained in step S4, the control unit 10 obtains a lubricant supply amount to be adjusted with respect to the amount (step 5).
It is assumed that the relationship between the amount of reverse transfer toner and the amount of lubricant supplied is recorded as a table in the storage unit 6.

The control unit 10 controls the contact force of the solid lubricant 472 with respect to the brush roller 471 in order to obtain the supply amount based on the lubricant supply amount to be adjusted (step S6). In the present embodiment, as in the first embodiment, the contact force of the solid lubricant 472 with the brush roller 471 is controlled by changing the set length of the spring 474c. It is assumed that the relationship between the lubricant supply amount and the spring 474c is recorded as a table in the storage unit 6.
In addition to the above, it is also possible to control the lubricant supply amount by the method shown in the first embodiment.

After the lubricant supply amount is set as described above, the control unit 10 starts printing (step S7) and ends the lubricant supply amount control.

As described above, the image forming apparatus 1 in the second embodiment calculates the amount of reverse transfer toner, and controls the amount of lubricant supplied to the photoconductor drum 41 of the downstream color based on the result. Therefore, since the amount of the lubricant supplied in the downstream color can be controlled according to the amount of the reverse transfer toner reaching the cleaning blade 46, the lubricant fluctuation range on the photoconductor drum 41 can be reduced.

The transfer voltage may be controlled as described above using the transfer voltage of each color, but the image area ratio is controlled by the order of the intermediate transfer belt 451 of the image forming section with respect to the rotation direction, and is influenced by the image forming section upstream thereof. Need to be considered. Only the yellow toner affects the magenta image forming part M, which is the second color image forming part from the upstream side, but the cyan image forming part C is affected by yellow toner and magenta toner, and the black image forming part K is affected by yellow toner and magenta. Toner and cyan toner affect.
Therefore, in order to control the amount of lubricant on the photoconductor drum 41 more accurately, it is preferable to obtain the amount of reverse transfer toner based on the image area ratio of all the colors on the upstream side of the self-coloring unit.
On the other hand, since the yellow toner of the most upstream color affects all the image-forming parts in the downstream, it is necessary to consider at least the image area ratio of the most upstream color in the nuclear image-forming part in the downstream.

Although the case of estimating the amount of reverse transfer toner reaching the cleaning blade 46 from the set transfer voltage has been described in the present embodiment, it is also possible to actually measure the amount of reverse transfer toner.
The amount of reverse transfer toner can be measured on the photoconductor drum 41 or on the intermediate transfer belt 451 using an optical density sensor. A case of measuring the amount of toner on the intermediate transfer belt 451 will be described. As shown in FIG. 14, density sensors SE1 and SE2 (measurement units) for measuring the amount of toner on the intermediate transfer belt 451 before and after entering the nip portion with the photoconductor drum 41 are provided. When the reverse transfer toner is generated, it passes through the nip portion with the photoconductor drum 41, so that the amount of toner on the intermediate transfer belt 451 is reduced. That is, the amount of toner detected by the density sensor SE2 arranged on the downstream side of the intermediate transfer belt 451 is smaller than the amount of toner detected by the density sensor SE1 arranged on the upstream side of the intermediate transfer belt 451. Therefore, the amount of reverse transfer toner can be obtained by calculating the difference in the amount of toner detected by the density sensors SE1 and SE2.
This amount of reverse transfer toner can be obtained from the output values of the upstream color toner density sensors SE1 and SE2 when a patch image of the upstream color is formed between the printed image and the image of the printed image and the own color is used as the background. You can. In this case as well, the amount of reverse transfer toner reaching the cleaning blade 46 changes depending on the image area ratio of the upstream color, so it is necessary to determine the amount of lubricant to be adjusted in consideration of the image area ratio.

[Other embodiments]
Although the above embodiments have been specifically described based on the embodiments of the present invention, the above embodiments are suitable examples of the present invention and are not limited thereto.

For example, the case where the lubricant coating mechanism 47 is provided on the upstream side of the cleaning blade 46 has been described, but as shown in FIG. 15, it may be provided on the downstream side of the cleaning blade 46.
Specifically, the recovery roller 473 provided in FIG. 3 is no longer necessary, and a flat plate-shaped leveling blade 475 made of an elastic body for leveling the lubricant supplied on the photoconductor drum 41 is provided.
Also in this configuration, the mechanism in which the lubricant on the photoconductor drum 41 is recovered by the cleaning blade 46 and the recovered amount is affected by the reverse transfer toner is the same, and the amount of the lubricant on the photoconductor drum 41 of each color is within a certain range. In order to control the color, it is necessary to supply less lubricant for the most upstream color than for the downstream color.
The control of the lubricant supply amount is the same as when the brush roller 471 is provided in the upstream portion of the cleaning blade 46.

Alternatively, as shown in FIG. 16, a developer obtained by externally adding lubricant particles to the toner may be used to supply the lubricant particles together with the toner to the photoconductor drum 41 in the developing apparatus 44.
Since the lubricant is supplied to the photoconductor drum 41 by the toner, the brush roller 471, the solid lubricant 472, and the recovery roller 473 are eliminated from the system of FIG.
Even in the toner external method, the lubricant on the photoconductor drum 41 is recovered by the cleaning blade 46, and the mechanism by which the recovered amount is affected by the reverse transfer toner is the same, and the amount of lubricant on the photoconductor drum 41 of each color is within a certain range. In order to control the color, it is necessary to supply less lubricant for the most upstream color than for the downstream color. Therefore, it is necessary to reduce the amount of lubricant contained in the toner of the most upstream color as compared with that of the downstream color.
In the toner external addition method, a brush roller 471 and a recovery roller 473 may be provided upstream of the cleaning blade 46.

In addition, the detailed configuration of each device constituting the image forming apparatus and the detailed operation of each device can be appropriately changed without departing from the gist of the present invention.

1 Image forming device 4 Image forming unit 41 Photoreceptor drum (image carrier)
42 Charging device 43 Exposure device 44 Developing device 45 Transfer device 451 Intermediate transfer belt (intermediate transfer body)
452 Transfer roller 46 Cleaning blade (cleaning member)
47 Lubricants application mechanism (lubricant supply device)
471 Brush roller (rotating member)
472 Solid lubricant 473 Recovery roller 474a Holding member 474b Guide 474c Spring (pressing member)
474d Eccentric cam 10 Control unit Y Yellow image forming unit (image forming device)
M Magenta image-making department (image-making device)
C Cyan image forming part (image forming device)
K Black image drawing part (image drawing device)
SE1, SE2 concentration sensor (measurement unit)

Claims (14)

An intermediate transfer body that transfers the toner image to paper,
A plurality of image-forming devices arranged along the rotation direction of the intermediate transfer member, and the like.
The image-making device is
An image carrier that supports a toner image to be transferred to paper,
A charging device for charging the image carrier and
A developing device that supplies toner to the image carrier and develops the toner image,
It is provided with a cleaning member which is arranged downstream of the transfer position with the intermediate transfer body and upstream of the charging device in the rotation direction of the image carrier and abuts on the image carrier to clean the surface.
A lubricant having the opposite polarity to the toner supplied by the developing device is supplied to the image carrier.
The amount of lubricant supplied to the image carrier of one image-forming device arranged at the uppermost stream in the rotational direction of the intermediate transfer member is smaller than the amount of lubricant supplied to the image-bearing body of the other image-bearing device. Moreover, the amount of toner transferred from the one image forming apparatus to the intermediate transfer body is an amount corresponding to the amount of reverse transfer toner which is the amount of toner reversely transferred from the intermediate transfer body to the other image forming apparatus. An image forming apparatus characterized by. An intermediate transfer body that transfers the toner image to paper,
A plurality of image-forming devices arranged along the rotation direction of the intermediate transfer member, and the like.
The image-making device is
An image carrier that supports a toner image to be transferred to paper,
A charging device for charging the image carrier and
A developing device that supplies toner to the image carrier and develops the toner image,
It is provided with a cleaning member which is arranged downstream of the transfer position with the intermediate transfer body and upstream of the charging device in the rotation direction of the image carrier and abuts on the image carrier to clean the surface.
The amount of lubricant supplied to the image carrier of one image-forming device arranged at the uppermost stream in the rotational direction of the intermediate transfer body is smaller than the amount of lubricant supplied to the image carrier of the other image-bearing device.
A lubricant supply device arranged downstream from the transfer position with the intermediate transfer member in the rotation direction of the image carrier and supplying the image carrier with a lubricant having the opposite polarity to the toner supplied by the developing device.
A control unit for controlling the amount of lubricant supplied in the lubricant supply device is further provided.
The control unit determines the amount of lubricant supplied in the lubricant supply device of the other image-forming device, the transfer voltage in the image-forming device, and the image area ratio of the toner image imaged in at least one image-forming device. An image forming apparatus characterized by being controlled based on. An intermediate transfer body that transfers the toner image to paper,
A plurality of image-forming devices arranged along the rotation direction of the intermediate transfer member, and the like.
The image-making device is
An image carrier that supports a toner image to be transferred to paper,
A charging device for charging the image carrier and
A developing device that supplies toner to the image carrier and develops the toner image,
It is provided with a cleaning member which is arranged downstream of the transfer position with the intermediate transfer body and upstream of the charging device in the rotation direction of the image carrier and abuts on the image carrier to clean the surface.
The amount of lubricant supplied to the image carrier of one image-forming device arranged at the uppermost stream in the rotational direction of the intermediate transfer body is smaller than the amount of lubricant supplied to the image carrier of the other image-bearing device.
A lubricant supply device arranged downstream from the transfer position with the intermediate transfer member in the rotation direction of the image carrier and supplying the image carrier with a lubricant having the opposite polarity to the toner supplied by the developing device.
A control unit for controlling the amount of lubricant supplied in the lubricant supply device is further provided.
The image-making device is
A measuring unit for measuring the amount of toner transferred from the intermediate transfer body to the image carrier is provided.
The control unit
The amount of lubricant supplied in the lubricant supply device of the other image-forming device is the amount of toner measured by the measuring unit in the image-forming device, and the image area ratio of the toner image imaged by at least one image-forming device. An image forming apparatus characterized by controlling based on and. An intermediate transfer body that transfers the toner image to paper,
A plurality of image-forming devices arranged along the rotation direction of the intermediate transfer member, and the like.
The image-making device is
An image carrier that supports a toner image to be transferred to paper,
A charging device for charging the image carrier and
A developing device that supplies toner to the image carrier and develops the toner image,
It is provided with a cleaning member which is arranged downstream of the transfer position with the intermediate transfer body and upstream of the charging device in the rotation direction of the image carrier and abuts on the image carrier to clean the surface.
The amount of lubricant supplied to the image carrier of one image-forming device arranged at the uppermost stream in the rotational direction of the intermediate transfer body is smaller than the amount of lubricant supplied to the image carrier of the other image-bearing device.
A lubricant supply device arranged downstream from the transfer position with the intermediate transfer member in the rotation direction of the image carrier and supplying the image carrier with a lubricant having the opposite polarity to the toner supplied by the developing device.
A control unit for controlling the amount of lubricant supplied in the lubricant supply device is further provided.
The lubricant feeder comprises a solid lubricant and
The hardness of the solid lubricant in the lubricant supply device of the one image-forming device is higher than the hardness of the solid lubricant in the lubricant supply device of the other image-forming device.
An image forming apparatus characterized in that the hardness of the solid lubricant is higher as the lubricant supply device of the image-forming apparatus arranged upstream in the rotation direction of the intermediate transfer body. The lubricant supply device is
A solid lubricant and a rotating member that abuts on the image carrier and rotates in contact with the solid lubricant are provided.
The control unit
The contact force of the solid lubricant with respect to the rotating member in the lubricant supply device of the one image-forming device is controlled to be weaker than the contact force of the solid lubricant with the rotating member of the lubricant supply device of another image-forming device. The image forming apparatus according to any one of claims 2 to 4, wherein the image forming apparatus is to be used. The lubricant supply device is
A solid lubricant and a rotating member that abuts on the image carrier and rotates in contact with the solid lubricant are provided.
The control unit
The claim is characterized in that the rotation speed of the rotating member in the lubricant supply device of the one image-forming device is controlled to be smaller than the rotation speed of the rotating member in the lubricant supply device of the other image-creating device. The image forming apparatus according to any one of 2 to 4. The lubricant supply device is
A solid lubricant and a pressing member that presses the solid lubricant against the image carrier are provided.
The control unit
The claim is characterized in that the pressing force of the pressing member in the lubricant supply device of the one image-forming device is controlled to be smaller than the pressing force of the pressing member in the lubricant supply device of another image-forming device. The image forming apparatus according to any one of 2 to 4. Any of claims 2 to 7, wherein the control unit controls so that the lubricant supply device of the image-forming device arranged upstream in the rotation direction of the intermediate transfer body has a smaller lubricant supply amount. The image forming apparatus according to one item. An intermediate transfer body that transfers the toner image to paper,
A plurality of image-forming devices arranged along the rotation direction of the intermediate transfer member, and the like.
The image-making device is
An image carrier that supports a toner image to be transferred to paper,
A charging device for charging the image carrier and
A developing device that supplies toner to the image carrier and develops the toner image,
It is provided with a cleaning member which is arranged downstream of the transfer position with the intermediate transfer body and upstream of the charging device in the rotation direction of the image carrier and abuts on the image carrier to clean the surface.
A lubricant having the opposite polarity to the toner supplied by the developing device is supplied to the image carrier.
The amount of lubricant supplied to the image carrier of one image-forming device arranged at the uppermost stream in the rotational direction of the intermediate transfer body is smaller than the amount of lubricant supplied to the image carrier of the other image-bearing device.
The developing device supplies toner to which a lubricant is added to the image carrier, and the developer supplies the toner.
The amount of the lubricant added to the toner in one image-forming device arranged at the uppermost stream in the rotational direction of the intermediate transfer member is smaller than the amount of the lubricant added to the toner in the other image-forming device. Image forming device. The image forming apparatus according to claim 9, wherein the image forming apparatus arranged upstream in the rotation direction of the intermediate transfer body has a smaller amount of lubricant added to the toner. The intermediate transfer body for transferring the toner image to the paper and a plurality of image forming devices arranged along the rotation direction of the intermediate transfer body are provided, and the image forming device carries the toner image to be transferred to the paper. Transfer between the image carrier, a charging device that charges the image carrier, a developer that supplies toner to the image carrier and develops a toner image, and an intermediate transfer member in the rotation direction of the image carrier. A cleaning member arranged downstream of the position and upstream of the charging device and in contact with the image carrier to clean the surface, and downstream of the transfer position of the intermediate transfer body in the rotation direction of the image carrier. An image forming apparatus computer provided with a lubricant supply device that is arranged and supplies the lubricant to the image carrier.
The lubricant supply amount in the lubricant supply device of one image-forming device arranged at the uppermost stream in the rotation direction of the intermediate transfer body is controlled to be smaller than the lubricant supply amount in the lubricant supply device of the other image-forming device. Control unit ,
To function as
The control unit
The amount of lubricant supplied in the lubricant supply device of the other image-forming device is controlled based on the transfer voltage in the image-forming device and the image area ratio of the toner image imaged in at least one image-forming device. program. The intermediate transfer body for transferring the toner image to the paper and a plurality of image forming devices arranged along the rotation direction of the intermediate transfer body are provided, and the image forming device carries the toner image to be transferred to the paper. Transfer between the image carrier, a charging device that charges the image carrier, a developer that supplies toner to the image carrier and develops a toner image, and an intermediate transfer member in the rotation direction of the image carrier. A cleaning member arranged downstream of the position and upstream of the charging device and in contact with the image carrier to clean the surface, and downstream of the transfer position of the intermediate transfer body in the rotation direction of the image carrier. An image forming apparatus computer provided with a lubricant supply device that is arranged and supplies the lubricant to the image carrier.
The lubricant supply amount in the lubricant supply device of one image-forming device arranged at the uppermost stream in the rotation direction of the intermediate transfer body is controlled to be smaller than the lubricant supply amount in the lubricant supply device of the other image-forming device. Control unit ,
To function as
The image-making device is
A measuring unit for measuring the amount of toner transferred from the intermediate transfer body to the image carrier is provided.
The control unit
The lubricant supply amount in the lubricant supply device of the other image-forming device is the toner amount measured by the measuring unit in the image-forming device, and the image area ratio of the toner image imaged by at least one image-forming device. And a program to control based on. An intermediate transfer body for transferring a toner image to paper and a plurality of image forming devices arranged along the rotation direction of the intermediate transfer body are provided, and the image forming device carries a toner image to be transferred to paper. Transfer between the image carrier, a charging device that charges the image carrier, a developing device that supplies toner to the image carrier and develops a toner image, and the intermediate transfer member in the rotation direction of the image carrier. A cleaning member arranged downstream of the position and upstream of the charging device and in contact with the image carrier to clean the surface, and downstream of the transfer position of the intermediate transfer body in the rotation direction of the image carrier. A lubricant supply device, which is arranged and supplies the lubricant to the image carrier, is provided.
The lubricant feeder comprises a solid lubricant and
The hardness of the solid lubricant in the lubricant supply device of one image-forming device is higher than the hardness of the solid lubricant in the lubricant supply device of another image-forming device.
The computer of the image forming apparatus having a higher hardness of the solid lubricant as the lubricant supply device of the image forming apparatus arranged upstream in the rotation direction of the intermediate transfer body is used.
The lubricant supply amount in the lubricant supply device of one image-forming device arranged at the uppermost stream in the rotation direction of the intermediate transfer body is controlled to be smaller than the lubricant supply amount in the lubricant supply device of the other image-forming device. Control unit ,
A program that functions as. An intermediate transfer body for transferring a toner image to paper and a plurality of image forming devices arranged along the rotation direction of the intermediate transfer body are provided, and the image forming device carries a toner image to be transferred to paper. Transfer between the image carrier, a charging device that charges the image carrier, a developing device that supplies toner to the image carrier and develops a toner image, and the intermediate transfer member in the rotation direction of the image carrier. A cleaning member arranged downstream of the position and upstream of the charging device and in contact with the image carrier to clean the surface, and downstream of the transfer position of the intermediate transfer body in the rotation direction of the image carrier. A lubricant supply device, which is arranged and supplies the lubricant to the image carrier, is provided.
The developing device supplies toner to which a lubricant is added to the image carrier, and the developer supplies the toner.
The computer of the image forming apparatus in which the amount of the lubricant added to the toner in one image forming apparatus arranged at the uppermost stream in the rotation direction of the intermediate transfer member is smaller than the amount of the lubricant added to the toner in the other image forming apparatus. of,
The lubricant supply amount in the lubricant supply device of one image-forming device arranged at the uppermost stream in the rotation direction of the intermediate transfer body is controlled to be smaller than the lubricant supply amount in the lubricant supply device of the other image-forming device. Control unit ,
A program that functions as.

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